Biodegradable film-based extraction of Emerging Contaminants: A sustainable strategy within the White Analytical Chemistry framework

The increasing awareness of the environmental impact of analytical procedures has heightened the demand for more sustainable methodologies. In response, the concept of White Analytical Chemistry (WAC) has been introduced, aiming to balance analytical performance, environmental sustainability, and operational efficiency [1]. Emerging contaminants (ECs) are a broad group of substances whose occurrence in the environment has attracted the attention of the scientific community over the last two decades [2]. Given the extremely low concentrations of ECs and the presence of interfering substances in environmental matrices, sophisticated instrumentation, such as liquid chromatographic coupled to mass spectrometry, is often required to achieve the necessary levels of specificity, accuracy, sensitivity and precision [3]. However, in accordance with WAC principles, it is crucial to adopt environmentally friendly sample preparation techniques. The objective, in this context, is to achieve accurate analytical results while minimizing the use of toxic reagents and the waste production. In this study, the potential of a biodegradable polymeric film (Mater-Bi) for the extraction of emerging contaminants from wastewater was initially investigated [4]. The optimized procedure allowed quantification of sixteen analytes from various classes, such as UV filters, pharmaceuticals, and additives, with satisfactory recoveries, precision, and minimal matrix effects. The film also demonstrated potential for extracting PerfluoroAlkyl Substances (PFAS), although different experimental conditions were needed for their extraction, prompting further targeted optimization. A more comprehensive study was then conducted, focusing on the extraction of over 60 emerging compounds from water samples. Scanning Electron Microscopy (SEM) analysis revealed that the internal structure of the film was porous, prompting investigations into different configurations to better understand its interaction with the analytes. While three setups were explored to enhance cross-sectional area, recoveries showed no substantial differences. Following this, a complete mass balance of the extraction procedure was conducted to identify where analyte loss occurred. It was observed that some analytes, particularly the more polar ones, did not interact strongly with the film, while others, especially PFAS, were not fully desorbed during the back-extraction step. To address these challenges, two experimental designs will be employed. First, a Mixture Process Design will be used to assess the influence of various variables (solvent type, % of acid, time, and ultrasound power) on the "conditioning" step of the film. Subsequently, a quadratic model will be applied to investigate the optimal conditions for back-extraction, aiming to achieve complete desorption of the analytes. In conclusion, this study presents a first approach with the green material Mater-Bi for the extraction of emerging contaminants. A multivariate optimization is currently underway to improve extraction efficiency and recovery rates, with the aim of expanding its applicability to a wider range of analytes, with particular attention to PFAS. This work contributes to the development of greener methodologies in environmental monitoring, paving the way for more sustainable and efficient approaches to the determination of emerging contaminants.